Energy is a basic industry of national economy and plays an important role in ensuring sustainable and stable development of economy and improvement of people's life quality. Since the beginning of the 21st century, economic society has been developed rapidly; science and technology have been innovated every day; the global population and economy have been growing constantly; and energy has been used more widely as the most fundamental driving power. As the anticipation of global depletion of non-renewable energy resources has been strengthened, the contradiction between energy supply and demand appeared. As is well known, industrial energy consumption, transportation energy consumption and building energy consumption are the three major components of global energy consumption. In particular, building energy consumption has been increased rapidly due to the continuous expanding of the total construction volume and the improvement of living comfort. Numerous studies have shown that solar radiation directly entering the room from the window is the main cause of indoor overheating in summer. About 29% of the energy in high-rise buildings comes from the radiant energy of sunlight. In hot climates, this figure can be close to 40%.
Intelligent and controllable sunshade film is an important development direction in the field of energy-saving building materials. Among them, the intelligent and temperature-controlled liquid crystal dimming film has the characteristic of automatically adjusting its light transmittance according to external temperature change, that is, when the weather is cold, the film is transparent, which does not affect indoor lighting and heating; when the weather is hot, the film automatically becomes into a light scattering state, which can shield most of the radiant energy of visible light and prevent indoor people's eyes from receiving strong sunlight. Also, the higher polymer content inside the film endows the film with a good bond strength, which is convenient for large-scale processing. Therefore, the intelligent and temperature-controlled liquid crystal dimming film has a good application prospect in the building energy-saving field.
Among the radiant energy of sunlight, visible light accounts for about 47%; whereas near-infrared light accounts for nearly 50%. Therefore, in order to further improve the thermal insulation performance of the intelligent and temperature-controlled liquid crystal dimming film, it is necessary to improve the film's capacity of absorbing near-infrared light.